Nonlinear observer based sliding mode control for a turbocharged diesel engine air-path equipped with EGR and VGT

In this paper, a nonlinear observer based sliding mode control (NOSMC) approach for air-path in the diesel engine equipped with a variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) is introduced. We propose a less conservative observer design technique for Lipschitz nonlinear systems using Ricatti equations, which works for significantly larger Lipschitz constants. The observer gains are obtained by solving the linear matrix inequality (LMI). Then a robust nonlinear control method, sliding mode control is applied for the states of intake and exhaust manifold pressure and compressor mass flow rate for the sake of the minimization of emissions. The proposed NOSMC controller is applied on a third-order mean value model of Turbocharged Diesel Engine (TDE). The robustness and efficiency of the proposed method are demonstrated by simulation results.